It works by splitting your signal into a high pass filter and low pass filter, panning between the two filters, and then mixing the two signals back together into a mono signal. The resulting effect lies somewhere between a tremolo and phase shifter.
The BYOC Brown Face Harmonic Tremolo is a semi-original design. It is an almost literal solid state translation of the harmonic tremolo circuit found in the 6G4-A, 6G5-A, 6G7-A, 6G12-A, and 6G13-A .
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